Several different types of water bugs make good pets and are likely to thrive in a small aquarium. Some of the insects that make the best pets include giant water bugs, water boatmen, whirligig beetles, dragon fly naiads and diving beetles. It is easy to set up an aquarium for your pet water bugs, and they are generally easy to acquire. You can order them from online pet retailers or catch them in your local pond, as long as it is legal to collect wild aquatic insects in your area.
Giant Water Bug
Giant water bugs are some of the most impressive aquatic insects that you can keep in an aquarium. With some species capable of reaching 2 1/2 inches in length, they can capture large prey like fish, frogs and small turtles by using their front limbs. Giant water bugs require perches in their enclosure, from which they will ambush prey as it passes by. A short tube that emerges from the abdomen of giant water bugs allows them to breathe while remaining underwater.
Water boatmen make interesting aquarium pets, and they have an unusual method for producing sounds to attract mates. Their sounds are rather quiet to observers standing near the aquarium, but their loud calls are quite powerful underwater. Scientists have recently determined that these insects produce the loudest sounds relative to their body size in the entire animal kingdom. Water boatmen subsist on algae and other organic debris found along the bottom of their habitat.
Whirligig beetles get their name from their habit of swimming around in rapid circles on the surface of small ponds and rivers. However, the small beetles are also quite skilled at swimming underwater, which helps them capture prey. Whirligig beetles may also serve important ecological roles, as they scavenge dead insects in addition to capturing live prey. Whirligig beetles are capable of locating flying or terrestrial insects that fall into the water by detecting the ripples made by the struggling prey.
While adult dragonflies spend their lives flying above ponds and rivers, the wingless nymphs – called naiads – spend their time underwater. Lacking the external gills of most other aquatic insects, dragonfly nymphs breathe by pumping water into their abdomens, where it passes through a set of internal gills. Naiads are skilled predators that catch prey like minnows, other insects and small frogs.
Like many other aquatic insects, diving beetles are active predators that spend much of their time foraging for prey. However, as captives, they often accept commercial fish flakes as a food source. Some species bear attractive colors, which can help to make your tank look more interesting. When frightened, diving beetles may exude a milky liquid that presumably deters predators. Unlike some other species, which have rather short life spans, diving beetles can live for two or three years. Predacious diving beetles can remain underwater for extended periods of time by trapping air bubbles between their wings and body.
Keeping most aquatic insects for pets is relatively simple. Use a 10-gallon aquarium for the enclosure, and fill the bottom with smooth river rocks. Add an air stone to keep the oxygen levels in the water adequate, but a filter is usually unnecessary. Some authorities recommend filling your tank with water from a clean local stream or river, while others recommend using bottled water or dechlorinated tap water. Add a few branches and live plants to provide the critters with places to hide and climb. Cover the aquarium with a screened lid and tape up all openings, as many aquatic insects are escape artists that are capable of flight.
Warning: Always use caution when handling water bugs, as some forms can deliver a very painful bite.
Feeding Your Friends
Some common aquatic insects, such as water boatmen, are scavengers, so feed them by adding a handful of dead leaves, a few algae-covered rocks and some organic debris from a local pond or river. Replace this food source periodically to ensure your bugs remain healthy. However, most commonly kept water bugs are predacious, meaning they require live animals, such as small fish, for food. You can purchase small feeder minnows at your local pet store, or you can collect them from local waterways, if it is legal to do so in your area. Keep a few minnows in the tank at all times, and allow your pets to catch and eat food as they wish. Mealworms are also suitable food for most aquatic insects. Feed each captive about one mealworm per week.